In GDAL warp you can simply set an xRes and yRes value. I'm trying to only use rasterio, but the process seems a lot less clear.
According to the docs https://rasterio.readthedocs.io/en/latest/topics/resampling.html you use a upscale or downscale factor to make a new cell resolution. Is there a way to just force a set value? For example, what if your new resolution doesn't divide evenly into your old one?
You just need to figure out the scale factor from your chosen and current pixel size, e.g. I want to resample this 10m resolution "input.tif" to 12.5m:
import rasterio from rasterio.enums import Resampling xres, yres = 12.5, 12.5 with rasterio.open("input.tif") as dataset: scale_factor_x = dataset.res[0]/xres scale_factor_y = dataset.res[1]/yres profile = dataset.profile.copy() # resample data to target shape data = dataset.read( out_shape=( dataset.count, int(dataset.height * scale_factor_y), int(dataset.width * scale_factor_x) ), resampling=Resampling.bilinear ) # scale image transform transform = dataset.transform * dataset.transform.scale( (1 / scale_factor_x), (1 / scale_factor_y) ) profile.update({"height": data.shape[-2], "width": data.shape[-1], "transform": transform}) with rasterio.open("output.tif", "w", **profile) as dataset: dataset.write(data) And here's how the output looks (a single red 10m pixel over the output 12.5m pixels in greyscale): 
